// 设置文件响应头的中间件
module.exports = async (ctx, next) => {
    const contentType = 'application/json; charset=utf-8'
    ctx.set('Content-Type', contentType)
    // 设置跨域访问
    ctx.set("Access-Control-Allow-Origin", "*")
    ctx.set("Access-Control-Allow-Methods", "OPTIONS, GET, PUT, POST, DELETE")
    // ctx.response.body = '{"success": true}'
    await next()
}